Gaskets & Seals

Ever since I got the engine back from the prop debacle, it's leaked at the oil sump and the nose seal. Nothing major (yet), but enough to make an annoying mess. So at 47.7 hours total time, I ordered some replacement gaskets and seals from Sacramento Sky Ranch.

To get to the oil sump gasket, I had to drop the intake and exhaust pipes. Then I lowered the sump with the the carb and control cables still attached. This gave me just enough room to swap out the old gasket. I dressed the new sump gasket with Permatex Hylomar sealant from the local auto parts store.

The Lycoming site encourages you to follow Service Instruction 1324A when installing the oil seal, but doesn't provide on-line access to said document. Luckily someone was nice enough to email it to me.

After removing the prop, I found the existing nose seal rotating freely in the engine case as if no sealant was used when it was installed. I carefully removed it with an exacto knife. It was replaced with a split nose seal and Pliobond 20 sealant.

A test run and hour-long test flight show both areas are leak free. I hope they stay that way!!

12/29/05 UPDATE: I planned to fly to lunch at KFQD with Len and our wives. I flew for an hour before lunch to burn some fuel for the fuel gauge calibration. We returned from lunch and an uneventful flight. I taxied to the hanger, shutdown and got out to find a rapidly growing puddle of oil underneath the cowl!! My replacement nose seal had failed after less than five hours of flight. Initially I was very ticked off, but then I realized how lucky I was that is failed on the ground, in front of my hanger, instead of over the mountains thirty minutes earlier!!

A second replacement seal, a non-split one this time, was installed with A & P help. It's doing fine so far after 1.6 hours of flight.

Original nose seal leak.

The second replacement seal ready to be glued in place.

The Lycoming Service Instruction recommends using Pliobond to glue the seal in place. I got it from ACS.